1. Field of Invention
Example embodiments of the present invention relate generally to wiring structures in semiconductor devices, methods of forming wiring structures, semiconductor devices including wiring structures, and methods of manufacturing semiconductor devices including wiring structures. More particularly, example embodiments of the present invention relate to a wiring structure in a semiconductor device capable of preventing a contact failure, a method of forming such a wiring structure, a semiconductor device including such a wiring structure, and a method of manufacturing a semiconductor device including such a wiring structure.
2. Description of the Related Art
As electronic devices such as computers or cellular phones continue to be widely used, semiconductor devices have rapidly improved. To meet various requirements of various devices, semiconductor device must typically have high response speeds and large storage capacities. Thus, semiconductor manufacturing technology continues to evolve so as to ensure a high degree of integration, improved reliability and high speed of the semiconductor device. When semiconductor devices become highly integrated, conductive wirings and contact plugs that transfer signals in the semiconductor device may have minute dimensions. That is, wirings and contact plugs in a conventional semiconductor device may have minute widths and an interval between the wirings may also be considerably reduced. As the widths of wirings in conventional semiconductor devices become smaller, it becomes more difficult to form the wirings by conventional manufacturing processes. Additionally, it may be difficult to form contact plugs that connect adjacent wirings at desired positions because contact plugs in conventional semiconductor device generally have a high aspect ratio. These problems of the conventional semiconductor device will be described as follows.
According to conventional semiconductor fabrication processes, a contact hole exposing a desired conductive wiring or an underlying contact plug is formed through an insulation layer by a photolithography process, and then the contact plug is formed in the contact hole. As the contact hole has a reduced size, an alignment error margin of the contact hole is also reduced. As a result, the likelihood that the contact hole will be misaligned relative to the conductive wiring or contact plug increases. If a misaligned contact hole exposes an undesired adjacent conductive wiring, the contact plug formed in the contact hole may cause a failure such as a bridge between adjacent conductive wirings.
After forming the contact hole through the insulation layer, a wet cleaning process or a wet etching process is usually performed using chemicals to enlarge a width of the contact hole. However, the chemicals may permeate into an underlying contact plug or conductive wiring when the cleaning process or the etching process is carried out excessively. As a result, the underlying contact plug or conductive wiring can become damaged. When damaged, the underlying contact plug or conductive wiring may contribute to an electrical failure of the semiconductor device. Generally, damage incurred by the underlying contact plug or conductive wiring increases as the alignment error of the contact plug increases. For example, when the chemicals permeate into upper portions or lateral portions of the underlying contact plug or conductive wiring, conductive material in the contact plug or conductive wiring may become melted or eroded by the chemicals. When the contact plug or the conductive wiring is partially melted or eroded by the chemicals, a contact resistance of the contact plug or conductive wiring can increase considerably or a contact failure of the contact plug or conductive wiring may occur. Recently, it has been discovered that the contact plug may incur serious damage by the permeated chemicals since the contact plug generally includes reactive metal or metal silicide.